I know, its a hell of a learning curve to get started. But, i think that should get you going enough to do this one. That being said, having a firm grasp of what you want the program to do is a great start!

These values are strings, since .getText() returns a String value. So, you have to convert them if you want to perform mathematical operations, so assuming the user can enter a decimal value, you should probably use doubles.

I have tried this but i cant seem to get the TextField1 2 and 3 to work i'm making a android app if it makes any difference and the user is putting the data in to a number TextField and its label is editText1 ,2,3and 4

Make sure that you have that listener code inside of your onCreate method. So it should be inside these brackets

Java Code:

public void onCreate(Bundle savedInstanceState) {
}

You should have that onCreate method at the top of your class, just make sure that the listener code falls somewhere inside there, maybe right below where you have
Button MyButton1 = (Button) findViewById(R.id.button1);

ok i think i have done all the suggestions people have given but now i'm a bit stuck. it asking me to "Change modifier to Final" and when i do that it then gives me an error and asks me to change it back, then goes round in a loop. here's my full code so you can have a look: